Watch Joe Biden surprise Ellen for her birthday

Vice President Joe Biden surprised Ellen DeGeneres on her birthday, using the opportunity on her show to ask people to sign up for Obamacare.

In an episode that aired Monday, Biden asked “every mom out there to tell their adult child between the ages of 26 and 35 sign up — for no other reason than give mom peace of mind.” He asked people to go to HealthCare.gov and call 1-800-318-2596 if they need someone to walk them through the process.

“It’s easy,” Biden said. “And it’s finally working — the website.”

For Obamacare, getting this particular age group to sign up isn’t just about giving moms peace of mind. (Though the White House has called on moms to help get young people signed up before.) Young adults tend to have lower health-care costs; if more of them sign up, that could help keep premiums lower. That would avoid what health wonks call a death spiral — when only sick people sign up, driving up costs and making health care less affordable for everyone.

The deadline to enroll for 2015 health coverage on HealthCare.gov is February 15.

For her birthday, Biden also gave DeGeneres a bath robe with a White House seal — and a present for her mom. “My mom used to have an expression,” Biden said. “She said, ‘Joey, on a child’s birthday the mother should get the gift because she did all the work.’”

Asked whether he was doing anything special with his wife for Valentine’s Day, Biden said they’re doing “a lot and I’m not going to tell you.”